[ARROW-16202] [C++][Parquet] WipeOutDecryptionKeys doesn't securely wipe out keys

• Type: Bug
• Status: Open
• Priority: Critical
• Resolution: Unresolved
• Affects Version/s: 7.0.0
• Fix Version/s: 11.0.0
• Component/s: C++, Parquet
• External issue URL: https://github.com/apache/arrow/issues/31603
• Assignee: Unassigned
• Reporter: Antoine Pitrou
• Created: 14/Apr/22 15:04
• Updated: 11/Jan/23 11:42

Description

InternalFileDecryptor::WipeOutDecryptionKeys() merely call std::string::clear to dispose of the decryption key contents, but that method is not guaranteed to clear memory (it probably doesn't, actually).

We should probably devise a portable wrapper function for the various OS-specific memory clearing utilities.